JP2009058824A - Developing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing method for a photosensitive planographic printing plate capable of producing a high-quality planographic printing plate. <P>SOLUTION: The developing method for a photosensitive planographic printing plate includes immersing an imagewisely exposed photosensitive planographic printing plate in a developer solution housed in a developing tank and replenishing the developer solution in the developing tank with a developer replenisher to maintain the activity of the developer solution within a given limit. In a time period after the developer tank is filled with a developer solution that is not used for developing a predetermined volume of planographic printing plates and until the fatigue degree of the developer solution reaches a limit Fa, a photosensitive planographic printing plate is immersed in the developing tank to develop; and after the fatigue degree of the developer solution reaches the limit Fa, replenishing the solution with a replenisher is started. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a development processing method for producing a photosensitive lithographic printing plate, and more particularly to a technique for developing a photosensitive lithographic printing plate by immersing it in a developer.

  In general, a photosensitive lithographic printing plate (hereinafter referred to as a lithographic printing plate) comprises an oleophilic image portion that receives ink in the printing process and a hydrophilic non-image portion that receives dampening water. Lithographic printing utilizes the property that water and printing ink repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). As described above, a difference in ink adhesion is caused on the surface of a lithographic printing plate, and after ink is applied only to an image portion, the ink is transferred to a printing medium such as paper and printed.

  In order to produce a lithographic printing plate, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support has been widely used. Usually, the lithographic printing plate precursor is exposed through an original image such as a lithographic film, and then the image portion of the image recording layer is left, and the other unnecessary image recording layer is removed with an alkaline developer or organic A lithographic printing plate is obtained by dissolving and removing with a solvent and exposing the surface of the hydrophilic support to form a non-image area.

  In the conventional plate making process of a lithographic printing plate precursor, after exposure, a step of dissolving and removing unnecessary image recording layers with a developer or the like is necessary. Treatment and less waste liquid are cited as issues. In particular, in recent years, the disposal of waste liquids accompanying wet processing has become a major concern for the entire industry due to consideration for the global environment, and thus the demand for solving the above problems has become stronger.

  On the other hand, in recent years, digitization technology for electronically processing, storing, and outputting image information by a computer has become widespread, and various new image output methods corresponding to such digitization technology will be put into practical use. It is becoming. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with that light, directly without using a lithographic film. Computer-to-plate technology for manufacturing is attracting attention. Accordingly, obtaining a lithographic printing plate precursor adapted to such a technique is one of the important technical issues.

  As mentioned above, the low alkali level of the developer and the simplification of the processing process are more strongly desired than ever in terms of consideration for the global environment and the adaptation to a small space and low running cost. It has become to. However, as described above, the development processing step generally comprises three steps: development with an alkaline developer having a pH of 10 or more, then pouring an alkaline agent in a water-washing bath, and then processing with a gum solution mainly composed of a hydrophilic resin. As a result, the automatic developing machine itself takes up a large space, and developing waste liquid, washing waste liquid and gum waste liquid are generated, leaving problems in terms of environment and running cost. Further, when a developer having a pH of 10 or higher is used for a long time as much as possible, a method of replenishing a dedicated replenisher so as not to decrease the activity of the developer is widely used. In the case of a developer, a neutralization reaction occurs due to carbon dioxide gas in the air, and replenishment is necessary to maintain the activity of the developer even if left as it is. In addition, when replenishing during processing, the same amount of developer is discharged from the overflow pipe by replenishment, so if the developing mother liquor is shortly after preparation, almost unprocessed new solution will be discarded. Was wasted.

On the other hand, for example, Patent Document 1 proposes a developing method using an alkaline solution containing a nonionic surfactant having a pH of 10 to 12.5, but the photosensitive composition contains an alkali-soluble polymer. However, there is a problem that development becomes impossible if the pH is lower than that.
For example, Patent Document 2 describes a lithographic printing plate precursor in which an image forming layer in which hydrophobic thermoplastic polymer particles are dispersed in a hydrophilic binder is provided on a hydrophilic support. This lithographic printing plate precursor is formed by image exposure using an infrared laser to form an image by coalescence of hydrophobic thermoplastic polymer particles by heat, and is then mounted on a cylinder of a printing machine, fountain solution and / or On-press development is possible with ink. However, the method of forming an image by merging the fine particles by simple thermal fusion exhibits good on-press developability, but the image strength (adhesion with the support) is extremely weak, and the printing durability is poor. Had the problem of being sufficient.

  Therefore, as a method for solving the above-mentioned problems, after recording an image on a lithographic printing plate precursor having a heat-sensitive layer containing a fine particle polymer on a support, an automatic processor equipped with a rubbing member is used in the presence of a developer. A method for producing a lithographic printing plate by removing the image recording layer of the non-exposed portion by rubbing the recording surface of the lithographic printing plate precursor with a rubbing member has been proposed (see Patent Document 3).

However, the reduction in alkali and the simplification of the process impose a great load on the development process. For example, the alkaline developer can easily dissolve and remove the photosensitive layer, but the low alkaline developer cannot easily remove the photosensitive layer. For this reason, the photosensitive layer that could not be dissolved inevitably remained on the plate again and became a residue on the plate, causing poor appearance and eventually smearing during printing. Further, sometimes the afterimaged photosensitive layer contaminates the inside of the processing machine, increasing the degree of time and labor required for maintenance.
As a method for replenishing the developer for such an immersion type lithographic printing plate,
(A) A method of adding an amount corresponding to the area of the printing plate to be processed after each plate or constant plate processing (Patent Document 4)
(B) The activity of the developing solution during processing is indicated by a direct or indirect index (for example, conductivity, pH,
There is a method of detecting by measuring viscosity, turbidity, etc.) and replenishing it with feedback control so as to recover the desired activity (Patent Document 5).
However, although the method (B) is not wasteful in principle, there is a drawback that manufacturing cost is required for the indicator detection equipment. Although the method (A) is low in cost, the developer is wasted. That is, when replenishment of the developer is started at the same time as the start of development, the charged liquid almost in the same amount as the replenishment amount is immediately discharged from the overflow pipe of the developing tank.

In addition, along with the reduction in alkali level and simplification of the process, the processing machine is not configured to be soaked in the developer, but should be of a horizontal transport type that transports horizontally and supplies the developer by spraying. There is also.
However, this horizontal conveyance type configuration has a problem that the liquid is easily scattered by the splashing of the liquid, and the scattered liquid is dried and formed into a residue. In essence, the horizontal conveyance type configuration easily dries the developer when it is not in operation, and the rubbing material (brush), the roller, etc. are also likely to become dirty due to drying, and the problem of debris from the dirt cannot be avoided. For this reason, the design of the horizontal conveyance type was very difficult and the technical hurdle was high.

JP 2002-91016 A Japanese Patent No. 2938397 Japanese Patent Laid-Open No. 2003-316021 Japanese Patent Publication No. 6-12435 JP-A-6-51532

  The present invention has been made in order to solve the above-described drawbacks of the automatic developing apparatus and the disadvantages of the conventional replenishment method, and provides a developing method for developing a photosensitive lithographic printing plate capable of producing a high-quality lithographic printing plate. The purpose is to provide.

The object of the present invention is achieved by the following configuration.
(1) Imagewise exposed photosensitive lithographic printing plate is developed by immersing it in a developer contained in a developer tank, and a developer replenisher is replenished to the developer in the developer tank to develop a developer activity. Is a development process for photosensitive lithographic printing that keeps within a certain limit,
After filling the developing tank with a predetermined volume of the lithographic printing plate with an undeveloped developer, the photosensitive lithographic printing plate is immersed in the developing tank until the fatigue level of the developer reaches the limit. A method for developing a photosensitive lithographic printing plate, in which replenishment of a development replenisher is started after development processing and the fatigue level of the developer reaches a limit.

  According to this photosensitive lithographic printing plate development processing method, the developer is not replenished at the initial stage of the development processing, and the development processing is performed until the development capacity of the developer initially charged in the developing tank reaches a limit, A predetermined developer replenishment amount is replenished immediately after reaching the limit of the developing ability. For this reason, it is possible to perform replenishment with almost no waste without wasting a developer with low fatigue. That is, in the conventional replenishing method, the amount of waste liquid increases linearly from the start, but according to the present invention, the developer is not replenished at the initial stage, so the cumulative amount of waste liquid decreases accordingly. Here, the limit of the fatigue level of the developer means a fatigue level that affects the image reproducibility on the photosensitive lithographic printing plate.

(2) The photosensitive lithographic printing plate development method according to (1), wherein the photosensitive layer of the photosensitive lithographic printing plate contains a polymerization initiator and a polymerizable compound.

  According to the development processing method of this photosensitive lithographic printing plate, it is necessary to pay special attention to safety in a system using a conventional high alkali developer, and it takes time and effort to process, and a polymerization initiator and a polymerizable monomer. In a lithographic printing plate precursor having a heat-sensitive layer containing, the problem of generation of dirt and debris can be solved. In addition, the computer-to-plate system using a photopolymerization type photosensitive material has a high photosensitivity and can increase the speed of plate making, and the cost of the exposure light source is relatively low, so it is widely used in the printing market. It is an important plate making system indispensable for the industry.

(3) The photosensitive lithographic printing plate as described in (1) or (2), wherein the developer in the developing tank has a pH of 2 to 10 and contains 5 to 30% by weight of a surfactant. Development processing method.

According to the development processing method of this photosensitive lithographic printing plate, by making the pH of the developer from 2 to 10, handling becomes much safer and there is no neutralization reaction by carbon dioxide in the air. Even if it is left as it is, the activity of the developer does not decrease. For this reason, the usage-amount (and waste amount) of a developing solution can be reduced.
By the way, since the pH of the developer of a normal lithographic printing plate is 12 or more, if the developer is left as it is, the pH is drastically lowered by carbon dioxide in the air, and the deterioration of the developer proceeds rapidly. Therefore, it is necessary to replenish the developer at regular intervals (replenishment with time), and conventionally, replenishment according to the processing area of the lithographic printing plate (treatment replenishment) and replenishment with time have been performed together. On the other hand, since the developer of the present invention has a pH of 2 to 10, a decrease in pH due to carbon dioxide is suppressed. As a result, the necessity for replenishment with time is reduced, and the replenishment of developer by process replenishment is mainly performed, and the management of the developer is simplified. Further, the pH drop due to carbon dioxide is reduced, and the life of the developer is prolonged.
Further, if the pH of the developer is 2 to 10, the developability of the lithographic printing plate is lowered. Therefore, by adding 5 to 30% by weight of the surfactant, this decrease in developability is complemented. Can do.

(4) Replenish the developer in the developer tank with an amount of water based on a preset amount of water evaporation of the developer per unit time to keep the developer concentration constant (1) to (3 ). The development processing method of the photosensitive lithographic printing plate of any one of 1).

  According to the development processing method of the photosensitive lithographic printing plate, the replenishment of the developer is not limited only to the area of the plate to be processed, but also to the concentration due to evaporation of water which is a component of the developer. Thus, stable development performance can be maintained over a long period of time. In other words, using an actual automatic processor, the amount of water evaporated per unit time from the developing unit in various atmospheric environments is obtained, and water is replenished according to the operating time and the stop time of the device, so that it is always stable. Development processing is possible.

According to the present invention, there is no waste of developer, and stable development performance can be obtained over a long period of time. In addition, it is possible to produce a photosensitive lithographic printing plate of a certain quality without causing the problem of contamination or residue in the automatic developing apparatus that is safe to handle.
In addition, since the developer is always kept at a constant level, good processing is always performed and the developer is replenished without waste, reducing the running cost by reducing the amount of developer replenishment and waste, and environmental In addition, it is possible to produce an advantageous lithographic printing plate.

  Hereinafter, preferred embodiments of a development processing method for a photosensitive lithographic printing plate according to the present invention will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is a configuration diagram of an automatic developing apparatus according to the first embodiment of the present invention.
As shown in FIG. 1, the automatic developing apparatus 100 develops a photosensitive lithographic printing plate (hereinafter referred to as “PS plate”) 4 and develops a developing unit 6 that performs gumming and a PS plate 4 after development. It is an immersion type lithographic printing automatic developing device provided with a drying unit 10 that performs the above.
An insertion port 14 is formed in the side plate 12 of the automatic developing apparatus 100, and the PS plate 4 inserted from the insertion port 14 is conveyed to the developing unit 6 by a conveyance roller (loading roller) 16. The insertion port 14 is provided with a rubber blade 18, and the insertion port 14 is closed by the rubber blade 18 when the PS plate 4 is not inserted. The plate detection sensor 27 detects the passage of the leading end of the inserted plate, sends a signal to the control device 50, and controls the developer supply pump 74 to replenish the developer 58.
In the developing tank 20 of the developing unit 6, a conveyance roller 22, a brush roller 24, and a squeeze roller 26 are sequentially provided from the upstream side in the conveyance direction, and a backup roller 28 is provided at an appropriate position therebetween. The PS plate 4 is immersed in the developing solution while being transported by the transport roller 22, and the brush roller 24 is rotated to remove the non-image portion of the PS plate 4 and be developed. This will be described in detail later.
The developed PS plate 4 is conveyed to the next drying 10 by a squeeze roller (unloading roller) 26.

The drying unit 10 is provided with a guide roller 36 and a pair of skewer rollers 38 in order from the upstream side in the transport direction. The drying unit 10 is provided with drying means such as hot air supply means and heat generation means (not shown). The drying unit 10 is provided with a discharge port 40, and PS is dried by a drying means.
The plate 4 is discharged from the discharge port 40. A shutter 44 is provided in the passage between the drying unit 10 and the developing unit 6, and the passage 46 is closed by the shutter 44 when the PS plate 4 does not pass through the passage 46.
The developing tank 20 is provided with a box-shaped shielding lid 60 integrally with the tank wall. The bottom wall of the shielding lid 60 is continuously curved in an arc shape so as not to come into contact with the upper outer peripheral surfaces of the transport roller 22, the brush roller 24, and the backup roller 28, and does not interfere with the roller or the like.

  Since the shielding lid 60 is box-shaped, an airtight space is defined in the upper part of the developing tank 20, and the amount of air in the developing unit 6 is reduced as much as possible. Further, since the shielding lid 60 is provided, the contact area between the developer and air is reduced as much as possible.

In the automatic developing apparatus 100 having the above-described configuration, the rubber blade 62 is arranged in contact with the carry-in roller 16 at the inlet, and the developing unit 6 is configured to be substantially airtight with respect to the external atmosphere, so that outside air does not flow in. It is like that.
In addition, a rubber blade 62 is disposed in contact with the squeeze roller 26 at the outlet of the developing unit 6 and is substantially airtight, so that air in the drying unit 10 does not flow into the developing unit 6. ing.
Therefore, the developing unit 6 has a hermetically sealed structure in which air flows in slightly when the PS plate 4 passes, but is substantially airtight and hardly receives air.
In addition, 98 is a display device that visually informs various necessary information, and 99 is an alarm device that informs by hearing.

Next, the developing unit 6 will be described in detail.
The developer tank 20 is connected with a first circulation pipe 80 for the developer. In the first circulation pipe 80, a developer circulation pump 71, a conductivity sensor 73, and a filter (not shown) are provided. The developer circulation pump 71 sucks the developer in the developer tank 20 from the suction hole at the bottom of the developer tank 20 into the first circulation pipe 80 and causes the developer to circulate through the first circulation pipe 80 and develop again. Discharge into the tank 20. The filter filters the developer flowing in the first circulation pipe 80. The electrical conductivity sensor 73 measures the electrical conductivity of the developer flowing in the first circulation pipe 80, and warns with an alarm when, for example, it is diluted by excessive steam evaporation correction.

  The developing unit 6 includes a second circulation pipe 90, a developer replenisher tank 55 connected to the second circulation pipe 90, and a developer supply pump 74 interposed in the second circulation pipe 90. The third circulation pipe 90a is provided, and the developer overflowed from the developing tank 20 is sent to the waste liquid tank 91 through the third circulation pipe 90a.

  More specifically, a pipe 90 for replenishing the developer 58 is provided in the vicinity of the developing tank 20. The other end (lower end in FIG. 1) of the pipe 90 for the developer 58 is connected to the developer replenishing tank 55, and a developer supply pump 74 is provided in the pipe. The developer supply pump 74 measures and supplies the developer 58 from the replenisher replenishment tank 55 to the developer tank 20. That is, the developer replenishing means is constituted by the pipe 90, the developer supply pump 74, and the replenisher replenishment tank 55. The replenishment with a new replenisher is performed to correct the concentration of the developer 58 or to recover a decrease in developing ability due to an increase in components that hinder the developing ability. Note that the components of the replenishing developer may be the same as or different from the starting solution initially charged in the developing tank depending on the photosensitive material and the developer component.

The developer supply pump 74 is controlled by a control device 50 having a control ROM and RAM 51 in which developer replenishment conditions and the like are stored, and a time measurement unit 52 based on the plate detection sensor 27 and the time measurement unit 52. . That is, the control device 50 controls the developer supply pump 74 based on the signal from the plate detection sensor 27 that can measure whether or not the plate has been conveyed and the plate area of the conveyed plate. Replenishment is performed based on the replenishment conditions stored in the control ROM and RAM 51 of the developer set according to the actual operating conditions of the developing device 2. As a result, the control device 50 replenishes the developer 58 in an amount corresponding to the replenishment condition from the developer replenishment tank 55 based on a replenishment timing described later. In actual replenishment, for example, replenishment may be performed for each processing of each plate, or each plate may be replenished after a plurality of plates have passed, instead of each plate.
The contact method of the PS plate 4 and the developer 58 in the developing unit 6 is roughly divided into a horizontal conveyance method and an immersion type conveyance method. In particular, in the immersion type, the PS plate 4 enters the developer 58 that is left stationary. Therefore, the contact is stable and reliable.

  In the automatic developing device 100, the image recording surface of the PS plate 4 that has passed through the conveying roller pair 16 on the carry-in side is rubbed by the brush roller 24, which is a rubbing member, with the image recording surface immersed in the developer 58, and PS Development is performed by removing the non-exposed portion of the image recording layer of the plate 4. Here, the rubbing of the developing solution 58 hardly occurs by rubbing while being immersed in the developing solution 58 filled in the developing tank 20. Thereby, contamination in the developing machine due to scattering and generation of debris do not occur. In particular, when rubbing in a state of being immersed in the developer 58 using a rotating brush roll, the rubbing member is in a state where 1/3 or more of the diameter is immersed in the developer 58 from the viewpoint of scattering of the solution. Is more preferable, and more preferably 1/2 or more is immersed.

In this configuration, since the developing tank 20 is provided, the lithographic printing original plate is conveyed below the developer surface, immersed in the developer 58, and conveyed in the developer 58.
The rubbing treatment with the rubbing member has a great effect when it is carried out after a certain time has passed after being immersed in the developer. In the development in this system, first, the developer 58 penetrates into the lithographic printing original plate photosensitive layer, and then the photosensitive layer can be easily removed from the non-image area. Therefore, it is possible to efficiently remove the photosensitive layer by pre-immersing in the developer 58 before performing the rubbing operation. According to the experiment, the elapsed time is 2 seconds or more after the part subjected to the removal operation is immersed in the liquid or wet with the liquid from the spray, more preferably 5 seconds or more, and further preferably 10 seconds or more. Since the development processing is normally performed within 60 seconds, the elapsed time is inevitably shorter than 50 seconds.

  Here, before immersing in the developer 58, the photosensitive layer of the PS plate can be brought into contact with the developer 58 using the spray tube S1 or the like. In this case, a fresh developer prepared in another tank may be sprayed. By bringing the photosensitive layer into contact with the developer 58, it is possible to increase the time until rubbing in the developer 58, so that development can be performed more efficiently. Further, by bringing the PS plate 4 into contact with the developing solution 58 before immersing the PS plate 4 in the developing solution 58, it is possible to appropriately shorten the time from when the PS plate 4 is immersed in the developing solution 58 until scraping. Further, in order to promote the penetration of the solution, a method of vibrating the PS plate 4 in a state where it is in contact with the developer 58 can be appropriately used.

Therefore, the time until the PS plate 4 comes out of the developer 58 after being immersed in the developer 58 is tsec.
In this case, the rubbing treatment with the rubbing material 24 is preferably performed after t / 2 seconds or after that. Therefore, it is desirable to perform the rubbing process in the middle or the latter half of the developing tank 20. Of course, the rubbing treatment can be performed in the first half of the developing tank if the developing tank 20 is lengthened or the conveying speed is slowed to increase the time of immersion in the developer 58. In order to always give a stable development process, the rubbing process with the rubbing material 24 is performed in the middle or the latter half.
Now, after developing using the rubbing member 24, the PS plate 4 exits the developer 58. The PS plate 4 having no stain can be obtained only in the treatment bath, and the steps after the treatment bath can be appropriately omitted.
Thus, after processing with only one bath, the drying unit 10 is provided, and the plate that has been desensitized simultaneously with development in the first bath is dried in the drying unit 10. In this way, when the treatment is completed with only one bath, the apparatus cost can be reduced and at the same time, the space can be saved.

  In the case of using an automatic developing device, for example, a method in which a developer 58 charged in a developer tank is pumped up by a pump and sprayed from a spray nozzle (see Patent Document 3), a submerged guide in a tank filled with the developer 58 Either a method of immersing and transporting the PS plate 4 original plate by a roll or the like, or a so-called disposable processing method of supplying and processing a substantially unused developer 58 for each plate as required, is generally used. Is used. Above all, from the viewpoint of preventing the liquid from scattering, the method of treating the PS plate 4 original plate by immersing it is excellent. Further, the PS plate 4 can be produced by an apparatus in which an exposure apparatus and an automatic developing apparatus are integrated.

  In the exposure processing by the exposure apparatus, the PS plate 4 original plate is exposed through a transparent original image having a line image, a halftone dot image or the like, or is exposed imagewise by laser beam scanning or the like using digital data. Examples of light sources suitable for exposure include carbon arc lamps, mercury lamps, xeno lamps, metal hydrado lamps, strobes, ultraviolet rays, infrared rays, and laser beams. A laser beam is particularly preferable, and examples include a solid-state laser and a semiconductor laser that emit infrared rays with a wavelength of 760 to 1200 nm, an ultraviolet semiconductor laser that emits light with a wavelength of 250 to 420 nm, an argon ion laser that emits visible light, and an FD-YAG laser. . Among these, from the viewpoint of simplification of plate making, a laser that emits infrared rays or ultraviolet rays that can be operated under white light or yellow light is preferable.

  The rubbing member used in the present invention may be any member as long as it can rub the image recording surface of the PS plate 4 original plate. In particular, the image recording surface can be rubbed by rotating around the rotation axis. It is preferable to use a known member (for example, a known channel brush, twisting brush, implantation brush, carpet brush, and Morton roller).

As channel brushes, long so-called channel brushes as disclosed in Japanese Utility Model Laid-Open Nos. 62-167253, 4-63447, 4-64128, and JP-A-6-186751. A (band-like brush) that is spirally wound around the surface of the roller body is used.

  As the torsion brush, the one in which a torsion brush is inserted into a spiral groove provided on the shaft as disclosed in JP-A-3-87832 and spirally wound around the shaft is used.

  As an implantation brush, what is created by the method of making a small hole in a shaft roller and implanting a brush material is used.

  As a carpet brush, an elongated belt in which a hair material is woven into a woven fabric is wound around the shaft roller as disclosed in JP 2001-5193 A and JP 2001-66788 A. Is used.

  As the Molton roller, a roller part disclosed in JP-A-10-198044 is covered with a cylindrical sliding contact material made of a fiber knitted fabric, and the end on the mounting side is tightened. it can.

When a rotating member is used as the rubbing member, the number of rotations of the rubbing member is preferably as fast as possible in order to improve the removability of the image recording layer of the non-exposed portion of the PS plate 4 original plate. From the viewpoints of durability, production cost, scattering of the developer 58 and damage to the exposed portion of the PS plate 4 original plate, 30 to 1000 rpm, more preferably 50 to 500 rpm is preferable.

  When using a brush as a rubbing member, the number of the brush should just be one or more, and may have more than one. In the case of two or more, one or more may be rotated in a direction opposite to the processing direction of the PS plate 4 original plate. Further, when a rotating rubbing member is used, the development processing may be performed while swinging the rubbing member in the direction of the rotation axis. By swinging the rubbing member in the rotational axis direction, the non-image part of the PS plate 4 original plate can be removed more efficiently, and a higher quality PS plate 4 can be produced.

  As the material of the brush used for the rubbing member, natural fibers such as horse hair and pig hair, artificial fibers, metal fibers, and the like are known, but artificial fibers are preferable from the viewpoint of chemical resistance. Man-made fibers include polyamides such as nylon 6, nylon 6,6, nylon 6,10, nylon 6,12 and nylon 12, polyesters such as polyethylene terephthalate and polybutylene terephthalate (PBT), polyacrylonitrile, poly (meta ) Polyacrylics such as alkyl acrylate, polyolefins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride and polyvinylidene chloride, celluloses such as acetyl cellulose, polyurethanes such as polyurethane, polyphenylene sulfite, ethylene tetrafluoride Fluorine resins such as ethylene copolymers and polyvinylidene fluoride are used, but considering elasticity, rigidity, wear resistance, heat resistance, chemical resistance, water supply, moisture absorption, etc., nylon 6, nylon 6, 6, Nylon 6 · 10, Nai 6/12, nylon 12, polypropylene, polybutylene terephthalate, and polyethylene terephthalate are preferable, and nylon nylon 6.6, nylon 6.10, 6.12, nylon 12, polybutylene terephthalate (PBT), and polypropylene are more preferable. It is done. Of the polyesters, polybutylene terephthalate (PBT) is particularly preferable. Of the polyolefins, polypropylene is particularly preferred.

  The thickness of the brush hair is not particularly limited, but is preferably 0.01 mm to 1.0 mm, more preferably 0.1 mm to 0.5 mm. This is because if the thickness of the brush is thinner than 0.01 mm, the rubbing property is inferior, and if it is thicker than 1.0 mm, the plate surface is easily scratched. Further, the length of the brush bristles is not particularly limited, but is usually in the range of 3 mm to 50 mm. This is because if the length is shorter than 3 mm, the contact with the PS plate 4 original plate becomes non-uniform and the plate surface is easily scratched. On the other hand, if the length is longer than 50 mm, no advantage in development processing can be found by increasing the length, which is disadvantageous economically. In the case of a Molton roller, since the cylindrical sliding contact material which consists of a knitted material is covered, regulation of the thickness and length of a hair material is unnecessary.

  As described above, according to the first embodiment, the PS plate 4 that has been desensitized simultaneously with development in the developing tank is dried in the drying unit 10. At the same time, it is possible to save space, and since development and rubbing are performed in the developer, liquid splashing due to liquid splashing can be achieved compared to a horizontal conveyance type automatic developing device that performs the same low alkali treatment. Therefore, the problem that the scattered liquid dries and becomes crushed is also solved.

Next, in the development processing by the automatic developing device 100, the development replenisher added to the developing tank 20 is replenished at the following replenishment timing.
First, the developing tank 20 is brought into an initial state filled with a predetermined volume of unprocessed developer replenisher. Thereafter, until the fatigue level of the filled developer 58 reaches the limit fatigue level at which the photosensitive layer of the PS plate 4 cannot be removed, the plurality of PS plates 4 are sequentially immersed in the developing tank for development processing. Repeat. Then, replenishment of the developing replenisher is started after the degree of fatigue of the developer 58 reaches the limit fatigue with the progress of development processing.

This is shown in FIG. FIG. 2 is a graph showing the relationship between the fatigue level of the developer and the cumulative amount of waste liquid with respect to the processing area. In the figure, a solid line indicates a state in the present embodiment, and a dotted line indicates a state according to a conventional replenishing method in which the developer is replenished from the initial stage. According to this, in the conventional replenishing method, the fatigue level gradually deteriorates, and the amount of waste liquid tends to increase linearly from the start. On the other hand, in the present invention, since the replenishment is not performed at the initial stage, the fatigue level linearly deteriorates, and the replenishment is started as soon as a certain limit Fa is reached. Therefore, the fatigue level maintains Fa. Further, since the accumulated amount of waste liquid is not replenished at the initial stage, the amount of waste liquid (ΔW) can be reduced by that amount.

  That is, when replenishment is started simultaneously with the start of development, the charged liquid almost in the same amount as the replenishment amount overflows and is discharged from the third circulation pipe 30a (see FIG. 1). Therefore, when the developing process is performed without replenishing until the developing ability of the initially charged developer reaches the limit Fa, the predetermined replenishment amount is replenished immediately after the processing area A1 is processed and the limit Fa is reached. Can be replenished with almost no waste. Thereby, the PS plate 4 can be developed without waste, and the running cost can be reduced.

  As described above, in the present embodiment, the exposed PS plate 4 is developed by immersing it in the developing tank 20 containing a developer containing a surfactant as a main component. When replenishing the developer replenisher to the developer 58 to keep the developer activity within a certain limit, the developer tank 20 is filled with a predetermined amount of untreated start developer, and then the fatigue of the start developer is increased. The PS plate 4 is immersed in the developing tank 20 for processing until the degree reaches the limit fatigue level Fa that affects the image reproducibility on the PS plate 4, and the fatigue level of the developer 58 is limited to the limit fatigue level. Since the replenishment of the development replenisher is started after reaching the degree Fa, the developer can be replenished efficiently, and as a result, the waste amount of the developer can be reduced.

The meaning of “marginal fatigue Fa” as used herein means that, after exposure, the dot area ratio of 50% on a plate developed with a fresh developer increases to, for example, 52%. This refers to the case where the developability of the part that is half-exposure in the peripheral part of the dot (hereinafter referred to as the fringe part) becomes slow. For example, when the dot area ratio increases by 2%, the reflection density of the finished print increases and the influence on tone reproduction can be visually recognized. Therefore, the limit of developing ability here refers to a degree of reduction that has a very slight but obvious effect on printing performance.
That is, in FIG. 2, the vertical axis represents the amount of increase in the dot area ratio of 50%. In the above case, if the dot area ratio of 52% is set as the limit, the limit fatigue degree Fa becomes 2%.
The permissible level of the dot area ratio varies depending on the user. That is, for the user, a dot area ratio of 51 to 60% is a preferable allowable level (limit fatigue level Fa is 1 to 10%), and more preferably 51 to 55% (limit fatigue level Fa is 1 to 5%). The most preferable value is 51 to 53% (the limit fatigue degree Fa is 1 to 3%).
The limit Fa for starting replenishment is controlled by the processing area of the plate. That is, the user sets a permissible limit value in advance (for example, when the 50% halftone dot area ratio is 52%, the permissible limit value Fa is 2%), the plate processing area until this limit value is reached, The data is stored in the automatic processor, and replenishment is started when the predetermined plate processing area is exceeded from the next processing.

  In a normal lithographic printing plate development process, the pH of the developer is 12 or more. Therefore, if the developer is left as it is, the pH is drastically lowered by carbon dioxide in the air, and the developer rapidly deteriorates. Therefore, it is necessary to replenish the developer at regular intervals (replenishment over time), and replenishment (processing replenishment) according to the processing area of the lithographic printing plate and replenishment over time are performed together. On the other hand, according to the development processing method of the present invention, since the pH of the developer is 2 to 10, the pH drop due to carbon dioxide is suppressed. As a result, the time until the critical fatigue level Fa is reached is increased, and the developer is not discharged from the developer tank until the critical fatigue level is reached, so the waste amount of the developer can be reduced. .

In addition, according to the development processing method of the present invention, the replenishment of the developer by the process replenishment is mainly performed, and the management of the developer is simplified. Further, the pH drop due to carbon dioxide is reduced, and the life of the developer is prolonged.
Further, when the pH of the developer is 2 to 10, the developability of the lithographic printing plate is lowered. Therefore, the surfactant is added in an amount of 5 to 30% by weight in order to improve the developability. As a result, it is possible to supplement the decrease in developability caused by the low pH, and maintain good developability.

<Second Embodiment>
The present invention is not limited to the one-bath configuration shown in the first embodiment, and the PS plate 4 after the development treatment can be subjected to water washing, drying treatment, and desensitization treatment as a matter of course. In that case, the internal space of the developer tank is shielded from the outside air, and the developer is circulated, so that the developer fatigue due to contact with air is slowed and wasted (non-circulating) According to this conventional apparatus, since the developer is collected even though it is not fatigued, there is no waste in terms of resource saving).

FIG. 3 is a block diagram of an automatic developing apparatus according to the second embodiment of the present invention.
In FIG. 3, reference numeral 200 denotes an automatic developing apparatus according to the second embodiment. In the automatic developing apparatus 200, the same reference numerals as those of the automatic developing apparatus 100 (FIG. 1) according to the first embodiment described above indicate the same functions, and thus the duplicated description is omitted.
In FIG. 3, the developing unit 6 is basically the same as FIG. 1, and the major difference is that it has a two-stage configuration in which the developer adhering to the developed PS plate 4 is washed away and the gum solution is applied downstream of the developing unit 6. The finisher unit 8 is provided, followed by the drying unit 10. In the developing tank 6 of FIG. 1, the developing process and the gumming process are performed simultaneously, but here the two processes are separated. Another difference is that the shutter 44 provided in the path between the developing unit 6 and the drying unit 10 moves to the path between the finisher unit 8 and the drying unit 10 in FIG.

In FIG. 3, the finisher portion 8 includes a first finisher portion 8a and a second finisher portion 8b. Each finisher section 8a, 8b is provided with transport rollers 30a, 30b for transporting the PS plate 4, and spray members 34a, 34b for spraying the gum solution in the finisher tanks 32a, 32b onto the PS plate 4. Then, the PS plate 4 after the development processing is applied by spraying the gum solution by the spray members 34a and 34b while being transported by the transport rollers 30a and 30b. The gum solution in the finisher tank 32b of the second finisher portion 8b on the downstream side is supplied by overflowing into the finisher tank 32a of the first finisher portion 8a on the upstream side. It may be supplied in the same manner by a pump or the like.
A shutter 44 is provided in the passage between the drying unit 10 and the finisher unit 8, and the passage 46 is closed by the shutter 44 when the PS plate 4 does not pass through the passage 46.

  Further, the second finisher tank 32 b is replenished with the gum solution in the gum solution tank 56 by the pump 77 and the replenishment diluent 57 in the replenishment diluent storage tank 53 is replenished by the replenishment diluent supply pump 78. Here, the replenishment ratio of the gum solution and the diluent is, for example, 1: 1. With this replenishment, the gum waste liquid overflowed from the first finisher tank 32a is collected in the waste liquid tank 91 in the same manner as the development waste liquid.

  In the automatic developing apparatus 200 having the above-described configuration, the rubber blade 62 is provided at an appropriate place, and the developing unit 6 to the second finisher unit 8b are substantially airtight with respect to the external atmosphere, so that the outside air does not flow in. It has become. Further, a space between the developing unit 6 and the first finisher unit 8a is substantially airtight by the rubber blade 62 so that air in the first finisher unit 8a does not flow into the developing unit 6. Therefore, the developing unit 6 has a hermetically sealed structure in which air flows in slightly when the PS plate 4 passes, but is substantially airtight and hardly receives air.

  As described above, according to the configuration of the second embodiment, the development process and the desensitization process are separated, so that replacement by liquid fatigue can be performed in each process, and each liquid is made independent. It can be used effectively. Moreover, since it is configured in the developing tank in the sealed space, evaporation can be suppressed. Further, since the development and rubbing processing is performed in the developer, the liquid splash due to the liquid splash is eliminated as compared with the horizontal conveyance type automatic developing apparatus as in the first embodiment. To solve the problem.

  Even in the above-described configuration, the amount of waste liquid can be reduced by replenishing the developer described in the first embodiment at the replenishment timing shown in FIG. 2, and the planographic printing plate can be produced without waste while reducing running cost. It can be developed.

<Third Embodiment>
Next, another automatic developing apparatus for carrying out the developing method according to the present invention will be described.
FIG. 4 is a block diagram of an automatic developing apparatus according to the third embodiment of the present invention.
In FIG. 4, reference numeral 300 denotes an automatic developing apparatus according to the third embodiment of the present invention. In the automatic developing apparatus 300, the same reference numerals as those of the automatic developing apparatus 100 (FIG. 1) according to the first embodiment of the present invention described above indicate the same functions, and thus the duplicated description is omitted.
In FIG. 4, the developing unit 6 is basically the same as FIG. The difference is that a pre-heating (pre-heating) part and a pre-water washing (pre-water washing) part are provided upstream of the developing part 6.
The preheating unit is installed upstream of the developing unit 6 in the transport direction, and has a function of maintaining the specified PS plate surface temperature for a specified time while transporting the PS plate.
The pre-washing unit is installed on the upstream side in the transport direction of the developing unit 6 and on the downstream side in the transport direction of the pre-heating unit, and has a function of cleaning and cooling the surface of the PS plate with washing water while transporting the PS plate. The PS plate that has passed through the pre-water washing section is automatically conveyed to the developing section 6 which is the next process in a washed state.
By introducing these steps, the quality such as printing durability can be improved or the quality can be stabilized.
In addition, although two processes of the said preheating part and a pre-water washing part may introduce both, either one may be introduce | transduced.

  Even in the above-described configuration, the amount of waste liquid can be reduced by replenishing the developer described in the first embodiment at the replenishment timing shown in FIG. 2, and the planographic printing plate can be produced without waste while reducing running cost. It can be developed.

  In the configuration of each of the above embodiments, the developer concentration in the developer tank is replenished (replenished over time) with an amount of water based on a preset amount of water evaporation of the developer per unit time. Is preferably kept constant. According to this, the replenishment of the developing solution is not only replenished in accordance with the area of the plate to be processed (processing replenishment), but also is made to cope with the concentration by evaporation of water which is a component of the developing solution. , Stable development performance can be maintained over a long period of time. In other words, using an actual automatic processor, the amount of water evaporated per unit time from the developing unit in various atmospheric environments is obtained, and water is replenished according to the operating time and the stop time of the device, so that it is always stable. Development processing is possible.

The results of developing the PS plate under the following conditions are shown below.
Automatic development apparatus Automatic development apparatus of FIG. 4 (automatic development apparatus of the third embodiment)
Developer tank capacity 22 liters,
Developer: (A) Aqueous solution 1 was prepared. The unit is [g]. The pH of the aqueous solution 1 was 4.3. This developer has a processing capacity capable of developing a 20 m ² plate in 1 liter.
8970 g of water
Anionic surfactant (the following chemical formula) 400 g

アラビアガム １５０ ｇ
酵素変性馬鈴薯澱粉 ４００ ｇ
ジオクチルスルホコハク酸エステルのナトリウム塩 ５０ ｇ
第一燐酸アンモニウム １０ ｇ
クエン酸 １０ ｇ
ＥＤＴＡ−４−ナトリウム塩 １０ ｇ
ｐＨ ４．３

Gum arabic 150 g
Enzyme-modified potato starch 400 g
Dioctyl sulfosuccinate sodium salt 50 g
Primary ammonium phosphate 10 g
Citric acid 10 g
EDTA-4-sodium salt 10 g
pH 4.3

Planographic printing plate precursor:
(Production of support)
In order to remove rolling oil on the surface of an aluminum plate (material 1050) having a thickness of 0.3 mm, a degreasing treatment was performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then the hair diameter was 0.3 mm. The aluminum surface was grained using three bundle-planted nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed thoroughly with water. This plate was etched by being immersed in a 25 mass% sodium hydroxide aqueous solution at 45 ° C for 9 seconds, washed with water, further immersed in 20 mass% nitric acid at 60 ° C for 20 seconds, and washed with water. The etching amount of the grained surface at this time was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode.
The current density is 30 A / dm ² at the peak current, and the auxiliary anode has 5% of the current flowing from the power source.
Was diverted. The amount of electricity in the nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode.
Then, water washing by spraying was performed.

Next, a 0.5% by mass hydrochloric acid aqueous solution (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. and nitric acid electrolysis under the condition of an electric quantity of 50 C / dm ² when the aluminum plate is an anode In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying.
The plate was provided with a DC anodized film of 2.5 g / m ² at a current density of 15 A / dm ² using 15% by mass sulfuric acid (containing 0.5% by mass of aluminum ions) as an electrolytic solution, then washed with water and dried.
The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

Next, the following undercoat liquid (1) was applied so that the dry coating amount was 10 mg / m ² to prepare a support used in the following experiments.

Undercoat liquid (1)
・ Undercoat compound (1) below 0.017g
・ Methanol 9.00 g
・ Water 1.00g

A photosensitive layer coating solution (1) having the following composition was bar-coated on the support provided with the undercoat layer, followed by oven drying at 70 ° C. for 60 seconds, and image recording with a dry coating amount of 1.1 g / m ² . A protective layer coating solution (1) having the following composition was applied thereon using a bar so that the dry coating amount would be 0.75 g / m ^2, and then at 125 ° C. for 70 seconds. The lithographic printing plate precursor was obtained by drying.

<Photosensitive layer coating solution (1)>
・ The following binder polymer (1) (weight average molecular weight 80,000) 0.54 g
・ Polymerizable compound 0.40g
Isocyanuric acid EO-modified triacrylate (manufactured by Toa Gosei Co., Ltd., Aronix M-315)
・ Polymerizable compound Ethoxylated trimethylolpropane triacrylate 0.08 g
(Nippon Kayaku Co., Ltd., SR9035, EO addition mole number 15, molecular weight 1000)
・ The following sensitizing dye (1) 0.06 g
・ The following polymerization initiator (2) 0.18 g
・ The following chain transfer agent (1) 0.07 g
・ 0.40 g of ε-phthalocyanine pigment dispersion
(Pigment: 15 parts by mass, dispersant Binder polymer (1): 10 parts by mass,
Solvent cyclohexanone / methoxypropyl acetate / 1-methoxy-2-propanol = 15 parts by mass / 20 parts by mass / 40 parts by mass)
・ Thermal polymerization inhibitor 0.01g
N-nitrosophenylhydroxylamine aluminum salt ・ The following water-soluble fluorosurfactant (1) 0.001 g
・ Polyoxyethylene-polyoxypropylene condensate 0.04g
(Asahi Denka Kogyo Co., Ltd., Pluronic L44)
・ Tetraethylamine hydrochloride 0.01g
・ 3.5 g of 1-methoxy-2-propanol
・ Methyl ethyl ketone 8.0g

Protective layer coating solution (1)
Polyvinyl alcohol (saponification degree 98 mol%, polymerization degree 500) 40 g
Polyvinylpyrrolidone (weight average molecular weight 50,000) 5g
Poly (vinyl pyrrolidone / vinyl acetate (1/1)) (weight average molecular weight 70,000) 0.5 g
Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.5g
950g of water
Development processing A total area of 2000 m ² was developed for about one month. Since the tank capacity in the apparatus is 22 liters, there is no replenishment up to 22 × 20 (m ² / liter) = 440 m ² . Thereafter, up to 2000 m ² was replenished at a rate of 50 cc / m ² , and the total amount used was (2000-440) × 50 = 78000 cc. The total amount of waste liquid was almost the same.

<Comparative example>
Automatic development apparatus Automatic development apparatus of FIG. 4 (automatic development apparatus of the third embodiment)
Developer tank capacity 22 liters Developer Same as Example
Development processing A total area of 2000 m ² was processed with replenishment of 50 cc / m ² over about one month.
The finish of the plate was the same as that of the example, but the total amount used reached 2000 × 50 = 10000 cc, and the example was reduced by about 20%.

<Developer>
The lithographic printing plate precursor in the present invention is image-exposed with a light source of 350 nm to 450 nm, and then the plate surface is rubbed with a rubbing member in the presence of an aqueous solution having a pH of 2 to 10, thereby forming a protective layer and a non-exposed portion of the photosensitive layer. It can be removed and an image can be formed on the surface of the aluminum plate support.
The aqueous solution used in the present invention is an aqueous solution having a pH of 2 to 10. For example, water alone or an aqueous solution containing water as a main component (containing 60% by mass or more of water) is preferable. In particular, an aqueous solution having the same composition as that of a generally known fountain solution, a surfactant (anionic, nonionic, An aqueous solution containing a cationic system or the like, or an aqueous solution containing a water-soluble polymer compound is preferable. In particular, an aqueous solution containing both a surfactant and a water-soluble polymer compound is preferable. The pH of the aqueous solution is more preferably 3-9, still more preferably 4-8.

  Examples of the anionic surfactant used in the present invention include fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid salts, linear alkyl benzene sulfonic acid salts, branched alkyl benzene sulfonic acid salts, Alkylnaphthalene sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfonates , Sulfated castor oil, sulfated beef tallow oil, fatty acid alkyl ester sulfate salts, alkyl sulfate ester salts, polyoxyethylene alkyl etherate ester salts, fatty acid monog Ceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styryl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkylphenyl ether phosphates, styrene -Partial saponifications of maleic anhydride copolymer, partial saponifications of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensate and the like. Among these, dialkyl sulfosuccinates, alkyl sulfate esters and alkyl naphthalene sulfonates are particularly preferably used.

  It does not specifically limit as a cationic surfactant used for this invention, A conventionally well-known thing can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

Nonionic surfactants used in the present invention include polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene. Oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc. Alcohol-type glycerol fatty acid ester, pentaerythritol fatty acid ester, sorbitol and sorbita Fatty acid esters of fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.

  These nonionic surfactants may be used alone or in admixture of two or more. In the present invention, ethylene oxide adduct of sorbitol and / or sorbitan fatty acid ester, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, polyhydric alcohol Fatty acid esters are more preferred.

Further, from the viewpoint of stable solubility or turbidity in water, the nonionic surfactant used in the aqueous solution of the present invention is HLB (Hydrophile-Lipophile).
The (Balance) value is preferably 6 or more, and more preferably 8 or more. Furthermore, the ratio of the nonionic surfactant contained in the aqueous solution is preferably 0.01 to 10% by weight, and more preferably 0.01 to 5% by weight. Further, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based surfactants can be used in the same manner.

The aqueous solution of the present invention may contain an organic solvent. Examples of the organic solvent that can be contained include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (manufactured by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), and aromatic hydrocarbons (toluene). , Xylene, etc.), or halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.), polar solvents such as alcohols and esters.
In addition, when the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. When the organic solvent is contained in the aqueous solution, it is safe and flammable. In view of the above, the concentration of the solvent is preferably less than 40% by weight.

  The aqueous solution of the present invention may contain a water-soluble polymer compound. Examples of water-soluble polymer compounds include soybean polysaccharide, modified starch, gum arabic, dextrin, fibrin derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan, polyvinyl alcohol and derivatives thereof, polyvinylpyrrolidone, Examples include polyacrylamide and acrylamide copolymers, vinyl methyl ether / maleic anhydride copolymers, vinyl acetate / maleic anhydride copolymers, styrene / maleic anhydride copolymers, and the like.

  A well-known thing can be used for the said soybean polysaccharide, for example, there exists a brand name Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and the thing of various grades can be used. What can be preferably used is one in which the viscosity of a 10% by mass aqueous solution is in the range of 10 to 100 mPa / sec.

As the modified starch, known ones can be used, and starch such as corn, potato, tapioca, rice and wheat is decomposed with acid or enzyme in the range of 5 to 30 glucose residues per molecule, and further in an alkali. It can be made by a method of adding oxypropylene or the like.
Two or more water-soluble polymer compounds can be used in combination. The content of the water-soluble polymer compound in the aqueous solution is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass.

  In addition to the above, the aqueous solution of the present invention may contain preservatives, chelate compounds, antifoaming agents, organic acids, inorganic acids, inorganic salts and the like.

  Preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzisothiazolin-3-one, benztriazole derivatives, amiding anidine derivatives, quaternary ammonium salts, pyridine, Derivatives such as quinoline and guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3diol, 1,1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used.

  Examples of the chelate compound include ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents.

  As the antifoaming agent, a general silicon-based self-emulsifying type, emulsifying type, or nonionic surfactant having a HLB of 5 or less can be used. Silicon antifoaming agents are preferred. Among them, emulsification dispersion type and solubilization can be used.

  Examples of organic acids include citric acid, acetic acid, succinic acid, malonic acid, salicylic acid, caprylic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, and organic phosphonic acid. . The organic acid can also be used in the form of its alkali metal salt or ammonium salt.

  Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, Examples include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate and the like.

[Lithographic printing plate precursor]
First, the planographic printing plate precursor used in the present invention will be described.

<Photosensitive layer>
The lithographic printing plate precursor used in the plate making method of the present invention has a negative photosensitive layer on which the photosensitive layer in the exposed area is cured. The negative photosensitive layer is not particularly limited, but is a radically polymerizable photosensitive layer containing a hydrophobic binder polymer, a polymerization initiator and a polymerizable compound from the viewpoint of easy development and good printing durability. Is preferred. Hereinafter, the components of the photosensitive layer will be described.

(Hydrophobic binder polymer)
As the hydrophobic binder polymer that can be used in the photosensitive layer of the present invention, a water-insoluble polymer is preferably used. Furthermore, the hydrophobic binder polymer that can be used in the present invention preferably contains substantially no acid group such as a carboxyl group, a sulfone group, and a phosphoric acid group. The acid value of the binder polymer (acid content per gram of polymer) Is expressed as a chemical equivalent number) is preferably 0.3 meq / g or less, and more preferably 0.1 meq / g or less.
That is, the hydrophobic binder polymer that can be used in the present invention is preferably insoluble in water and an aqueous solution of pH 10 or higher, and the solubility of the hydrophobic binder polymer in water and an aqueous solution of pH 10 or higher is 0.5% by mass or less. Preferably, it is 0.1% by mass or less. By using such a hydrophobic binder polymer, the film strength, water resistance, and inking property of the photosensitive layer are improved, and printing durability is improved.

As the hydrophobic binder polymer, as long as the performance of the lithographic printing plate of the present invention is not impaired, a conventionally known one can be used without limitation within the above range, and a linear organic polymer having a film property is preferable.
As an example of such a hydrophobic binder polymer, a polymer selected from acrylic resin, polyvinyl acetal resin, polyurethane resin, polyamide resin, epoxy resin, methacrylic resin, styrene resin, and polyester resin is preferable. Especially, an acrylic resin is preferable and a (meth) acrylic acid ester copolymer is preferable. More specifically, an alkyl (meth) acrylate or an aralkyl ester and an ester residue (—COOR) of (meth) acrylate ester may have —CH ₂ CH ₂ O— unit or —CH ₂ CH ₂ NH— unit as R. A copolymer with a (meth) acrylic acid ester containing is particularly preferred. The preferable alkyl group of the (meth) acrylic acid alkyl ester is an alkyl group having 1 to 5 carbon atoms, and a methyl group is more preferable. Preferable (meth) acrylic acid aralkyl esters include benzyl (meth) acrylate.

Furthermore, the hydrophobic binder polymer can be provided with a crosslinking property in order to improve the film strength of the image area.
In order to impart crosslinkability to the binder polymer, a crosslinkable functional group such as an ethylenically unsaturated bond may be introduced into the main chain or side chain of the polymer. The crosslinkable functional group may be introduced by copolymerization or may be introduced by a polymer reaction.

  Here, the crosslinkable group is a group that crosslinks the polymer binder in the process of radical polymerization reaction that occurs in the photosensitive layer when the lithographic printing plate precursor is exposed. Although it will not specifically limit if it is a group of such a function, For example, an ethylenically unsaturated bond group, an amino group, an epoxy group etc. are mentioned as a functional group which can be addition-polymerized. Moreover, the functional group which can become a radical by light irradiation may be sufficient, and as such a crosslinkable group, a thiol group, a halogen group, an onium salt structure etc. are mentioned, for example. Especially, an ethylenically unsaturated bond group is preferable and the functional group represented by the following general formula (1)-(3) is especially preferable.

In the general formula (1), R ^{1 to} R ³ each independently represents a monovalent organic group, but R ¹
As preferable examples thereof, a hydrogen atom or an alkyl group which may have a substituent may be used. Among them, a hydrogen atom or a methyl group is preferable because of high radical reactivity. R ² and R ³ are each independently a hydrogen atom, a halogen atom, an amino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an optionally substituted alkyl group, or a substituted group. An aryl group that may have a group, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, an alkylamino group that may have a substituent, and a substituent An arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, a substituent An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.

X represents an oxygen atom, a sulfur atom, or N (R ¹² ) —, and R ¹² represents a hydrogen atom or a monovalent organic group. Here, examples of R ¹² include an alkyl group which may have a substituent. Among them, a hydrogen atom, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.

  Here, examples of the substituent that can be introduced include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, an aryloxy group, a halogen atom, an amino group, an alkylamino group, an arylamino group, a carboxyl group, an alkoxycarbonyl group, A sulfo group, a nitro group, a cyano group, an amide group, an alkylsulfonyl group, an arylsulfonyl group and the like can be mentioned.

In the general formula (2), R ⁴ to R ⁸ is each independently a monovalent organic group, R ⁴
To R ⁸ is preferably a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, an alkyl group which may have a substituent, An aryl group that may have a substituent, an alkoxy group that may have a substituent, an aryloxy group that may have a substituent, an alkylamino group that may have a substituent, and a substituent Arylamino group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, and the like. Among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, a substituent may be mentioned. The alkyl group which may have and the aryl group which may have a substituent are preferable.

Examples of the substituent that can be introduced are the same as those in the general formula (1). Y represents an oxygen atom, a sulfur atom, or N (R ¹² ) —. R ¹² has the same meaning as R ¹² in general formula (1), and preferred examples are also the same.

In the general formula (3), R ⁹ preferably includes a hydrogen atom or an alkyl group which may have a substituent. Among them, a hydrogen atom or a methyl group has high radical reactivity. preferable. R ¹⁰ and R ¹¹ are each independently a hydrogen atom, a halogen atom, an amino group, a dialkylamino group, a carboxyl group, an alkoxycarbonyl group, a sulfo group, a nitro group, a cyano group, or an alkyl group which may have a substituent. An aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylamino group which may have a substituent, a substituent An arylamino group that may have, an alkylsulfonyl group that may have a substituent, an arylsulfonyl group that may have a substituent, and the like, among them, a hydrogen atom, a carboxyl group, an alkoxycarbonyl group, An alkyl group which may have a substituent and an aryl group which may have a substituent are preferable because of high radical reactivity.

Here, examples of the substituent that can be introduced are the same as those in the general formula (1). Further, Z is an oxygen atom, a sulfur atom, -N (R ¹³⁾ -, or a phenylene group which may have a substituent. Examples of R ¹³ include an alkyl group which may have a substituent. Among them, a methyl group, an ethyl group, and an isopropyl group are preferable because of high radical reactivity.
Among these, (meth) acrylic acid copolymers having a crosslinkable group in the side chain and polyurethane are more preferable.

  Hydrophobic binder polymers having crosslinkability include, for example, free radicals (polymerization initiation radicals or growth radicals in the polymerization process of a polymerizable compound) added to the crosslinkable functional group, and polymerization of polymerizable compounds directly between polymers. Addition polymerization through a chain forms a cross-link between polymer molecules and cures. Alternatively, atoms in the polymer (eg, hydrogen atoms on carbon atoms adjacent to the functional bridging group) are abstracted by free radicals to form polymer radicals that are bonded to each other so that crosslinking between the polymer molecules occurs. Forms and cures.

  The content of the crosslinkable group in the hydrophobic binder polymer (content of unsaturated double bond capable of radical polymerization by iodine titration) is preferably 0.1 to 10.0 mmol, more preferably 1 g per 1 g of the hydrophobic binder polymer. Is 1.0 to 7.0 mmol, most preferably 2.0 to 5.5 mmol.

  Further, it is preferable that the binder polymer is hydrophilic from the viewpoint of improving developability with respect to an aqueous solution, and it is important that the binder polymer is compatible with the polymerizable compound contained in the photosensitive layer from the viewpoint of improving printing durability. Yes, ie lipophilic. From such a viewpoint, in the present invention, it is also effective to copolymerize a hydrophilic group and a lipophilic group in a hydrophobic binder polymer in order to improve developability and printing durability. Examples of the hydrophilic group include a hydroxy group, a carboxylate group, a hydroxyethyl group, an ethyleneoxy group, a hydroxypropyl group, a polyoxyethyl group, a polyoxypropyl group, an amino group, an aminoethyl group, an aminopropyl group, and an ammonium group. And those having a hydrophilic group such as an amide group or a carboxymethyl group.

The hydrophobic binder polymer preferably has a weight average molecular weight of 5,000 or more, more preferably 10,000 to 300,000, and a number average molecular weight of 1,000 or more, preferably 2000 to 250,000. Is more preferable. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.
The hydrophobic binder polymer may be any of a random polymer, a block polymer, a graft polymer, and the like, but is preferably a random polymer.

The hydrophobic binder polymer may be used alone or in combination of two or more.
The content of the hydrophobic binder polymer is 5 to 90% by mass, preferably 10 to 70% by mass, and more preferably 10 to 60% by mass with respect to the total solid content of the photosensitive layer. Within this range, good image area strength and image formability can be obtained.

(Polymerization initiator)
The polymerization initiator used in the present invention is a compound that initiates and accelerates the polymerization of a compound having a polymerizable unsaturated group by generating radicals by light or thermal energy. As such a radical generator, a known polymerization initiator or a compound having a bond having a small bond dissociation energy can be appropriately selected and used.

  Examples of the compounds that generate radicals include organic halogen compounds, carbonyl compounds, organic peroxides, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boron compounds, disulfone compounds, and oximes. Examples thereof include ester compounds and onium salt compounds.

  Specific examples of the organic halogen compound include Wakabayashi et al., “Bull Chem. Soc Japan” 42, 2924 (1969), US Pat. No. 3,905,815, Japanese Patent Publication No. 46-4605, JP 48-36281, JP 53-133428, JP 55-3070, JP 60-239736, JP 61-169835, JP 61-169837, JP 62- 58241, JP-A 62-212401, JP-A 63-70243, JP-A 63-298339, P. The compound as described in Hutt, "Journal of Heterocyclic Chemistry", 1 (No. 3) (1970) is mentioned. Of these, oxazole compounds and S-triazine compounds substituted with a trihalomethyl group are preferred.

Examples of the carbonyl compound include benzophenone, Michler ketone, 2-methylbenzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2-chlorobenzophenone, 4-bromobenzophenone, and the like.

  As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  Examples of the metallocene compound include JP-A-59-152396, JP-A-61-151197, JP-A-63-41484, JP-A-2-249, JP-A-2-4705, Examples include various titanocene compounds described in Kaihei 5-83588, and iron-arene complexes described in JP-A-1-152109.

  Examples of the hexaarylbiimidazole compound include the specification of JP-B-6-29285, U.S. Pat. Nos. 3,479,185, 4,311,783, and 4,622,286. And various compounds described in 1. above.

  Examples of the organic boron compound include organic borates described in JP-A No. 2002-116539 and Kunz, Martin “Rad Tech '98. Proceeding April 19-22, 1998, Chicago”, and the like. JP-A-6-157623, JP-A-6-175564, JP-A-6-175561, organoboron sulfonium complexes or organoboron oxosulfonium complexes, JP-A-6-175554, JP-A-6-175553 Organoboron iodonium complexes described in JP-A-9-188710, organoboron phosphonium complexes described in JP-A-9-188710, JP-A-6-34881, JP-A-7-128785, JP-A-7-140589, JP-A-7 -306527, JP, Organoboron transition metal coordination complexes of JP-like 7-292014 are exemplified.

Examples of the disulfone compound include JP-A Nos. 61-166544 and 2003-3.
And compounds described in Japanese Patent No. 28465.

  Examples of the oxime ester compound include JCS Perkin II (1979) 1653-1660), JCSPerkin II (1979) 156-162, Journal of Photopolymer Science and Technology (1995) 202-232, and JP-A 2000-66385. And compounds described in JP 2000-80068 A.

  Examples of the onium salt compound include S.I. I. Schlesinger, Photogr. Sci. Eng. 18, 387 (1974), T .; S. Diazonium salts described in Bal et al, Polymer, 21, 423 (1980), ammonium salts described in US Pat. No. 4,069,055, JP-A-4-365049, etc., US Pat. No. 4,069 , 055, 4,069,056, phosphonium salts described in European Patent Nos. 104,143, US Pat. Nos. 339,049, 410,201, JP -150848, JP-A-2-296514, iodonium salts, European Patent Nos. 370,693, 390,214, 233,567, 297,443, and 297 442, U.S. Pat. Nos. 4,933,377, 161,811, 410,201, 339,049, 4,760,013 No. 4,734,444, No. 2,833,827, German Patent No. 2,904,626, No. 3,604,580, No. 3,604,581 Or a sulfonium salt described in J. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as arsonium salts.

In the present invention, these onium salts function not as acid generators but as ionic radical polymerization initiators.
The onium salts preferably used in the present invention are represented by the following general formulas (RI-I) to (RI-II).
An onium salt represented by I).

In the formula (RI-I), Ar ₁₁ represents an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents. From the viewpoint of stability, a perchlorate ion, a hexafluorophosphate ion, Tetrafluoroborate ions, sulfonate ions and sulfinate ions are preferred.

In the formula (RI-II), Ar ₂₁ and Ar ₂₂ each independently represent an aryl group having 20 or less carbon atoms which may have 1 to 6 substituents, and preferred substituents include 1 to 12 alkyl groups, an alkenyl group having 1 to 12 carbon atoms, an alkynyl group having 1 to 12 carbon atoms, an aryl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 1 to 12 carbon atoms, Halogen atom, C1-C12 alkylamino group, C1-C12 dialkylamino group, C1-C12 alkylamide group or arylamide group, carbonyl group, carboxyl group, cyano group, sulfonyl group, carbon Examples thereof include a thioalkyl group having 1 to 12 carbon atoms and a thioaryl group having 1 to 12 carbon atoms. Z _21- represents a monovalent anion. Specifically, perchlorate ion, hexafluorophosphate ion, tetrafluoroborate ion, sulfonate ion, sulfinate ion, and carboxylate ion are preferable from the viewpoints of stability and reactivity.

In the formula (RI-III), R ₃₁ , R 32 and R ₃₃ are each independently an aryl group, alkyl group, alkenyl group or alkynyl group having 20 or less carbon atoms, which may have 1 to 6 substituents. Represents. Among them, an aryl group is preferable from the viewpoint of reactivity and stability. Z31- is 1
Represents a valent anion. As specific examples, perchlorate ions, hexafluorophosphate ions, tetrafluoroborate ions, sulfonate ions, sulfinate ions, and carboxylate ions are preferable in terms of stability and reactivity. More preferred are the carboxylate ions described in JP-A No. 2001-343742, and particularly preferred are the carboxylate ions described in JP-A No. 2002-148790.

  The polymerization initiator is not limited to the above, but a triazine-based initiator, an organic halogen compound, an oxime ester compound, a diazonium salt, an iodonium salt, and a sulfonium salt are more preferable from the viewpoints of reactivity and stability.

These polymerization initiators may be used alone or in combination of two or more.
Moreover, these polymerization initiators may be added to the same layer as other components, or another layer may be provided and added thereto. These polymerization initiators are preferably from 0.1 to 50% by mass, more preferably from 0.5 to 30% by mass, particularly preferably from 0.8 to 20% by mass, based on the total solid content constituting the photosensitive layer. Can be added.

(Infrared absorber)
In the photosensitive layer of the lithographic printing plate precursor that performs imagewise exposure using a light source that emits infrared rays, an infrared absorber can be used in combination with the polymerization initiator. In general, an infrared absorber has a function of converting absorbed infrared rays into heat, and the polymerization initiator is thermally decomposed by the heat generated at this time to generate radicals. The infrared absorber used in the present invention is a dye or pigment having an absorption maximum at a wavelength of 760 to 1200 nm.

  As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes Is mentioned.

  Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes.

Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, CMC Publishing, 1984) can be used.

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments , Quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like. Among these pigments, carbon black is preferable.

  The particle diameter of the pigment is preferably in the range of 0.01 to 10 μm, more preferably in the range of 0.05 to 1 μm, and particularly preferably in the range of 0.1 to 1 μm. Within this range, good stability of the pigment dispersion in the photosensitive layer coating solution and good uniformity of the photosensitive layer can be obtained.

  The addition of these infrared absorbers to the photosensitive layer is preferably made the minimum necessary amount in order to suppress side effects that inhibit the polymerization reaction.

  These infrared absorbers may be added in a proportion of 0.001 to 50% by mass, preferably 0.005 to 30% by mass, particularly preferably 0.01 to 10% by mass, based on the total solid content of the photosensitive layer. it can. Within this range, high sensitivity can be obtained without adversely affecting the uniformity and film strength of the photosensitive layer.

(Sensitizing dye)
Radical generation efficiency can also be increased by using a sensitizing dye in combination with the polymerization initiator in the photosensitive layer of a lithographic printing plate precursor that performs imagewise exposure using a light source that emits light of 250 to 420 nm. .

  Specific examples of the sensitizing dye include benzoin, benzoin methyl ether, benzoin ethyl ether, 9-fluorenone, 2-chloro-9-fluorenone, 2-methyl-9-fluorenone, 9-anthrone, and 2-bromo-9-anthrone. 2-ethyl-9-anthrone, 9,10-anthraquinone, 2-ethyl-9,10-anthraquinone, 2-t-butyl-9,10-anthraquinone, 2,6-dichloro-9,10-anthraquinone, xanthone 2-methylxanthone, 2-methoxyxanthone, thioxanthone, benzyl, dibenzalacetone, p- (dimethylamino) phenyl styryl ketone, p- (dimethylamino) phenyl p-methylstyryl ketone, benzophenone, p- (dimethylamino) ) Benzophenone (or Michalake) Emissions), p- (diethylamino) benzophenone, benzanthrone, 2,5-bis (4-diethylamino-phenyl) such as 1,3,4-oxadiazole and the like.

  These sensitizing dyes are preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 0.8 to 20% by mass with respect to the total solid content constituting the photosensitive layer. Can be added.

(Polymerizable compound)
The polymerizable compound used for the photosensitive layer in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and is a compound having at least one terminal ethylenically unsaturated bond, preferably two or more. To be elected. Such a compound group is widely known in the industrial field, and can be used without any particular limitation in the present invention. These have chemical forms such as monomers, prepolymers, i.e. dimers, trimers and oligomers, or mixtures thereof and copolymers thereof. Examples of monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and esters and amides thereof. In this case, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound, or an amide of an unsaturated carboxylic acid and an aliphatic polyvalent amine compound is used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxyl group, amino group or mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and monofunctional or polyfunctional A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid.

(Microcapsule)
In the present invention, as a method for causing the photosensitive layer to contain the above-described photosensitive layer constituents and other constituents described later, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, A part of the components can be encapsulated in microcapsules and added to the photosensitive layer. In that case, each component can be contained in any ratio in and out of the microcapsule.

  A preferable microcapsule wall used in the present invention has a three-dimensional cross-linking and has a property of swelling with a solvent. From such a viewpoint, the wall material of the microcapsule is preferably polyurea, polyurethane, polyester, polycarbonate, polyamide, and a mixture thereof, and particularly preferably polyurea and polyurethane. Moreover, you may introduce | transduce into the microcapsule wall the compound which has crosslinkable functional groups, such as an ethylenically unsaturated bond which can be introduce | transduced into said water-insoluble polymer.

  The average particle size of the microcapsules is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is further more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

(Other photosensitive layer components)
The photosensitive layer of the present invention can further contain various additives as required.
These will be described below.

(Surfactant)
In the present invention, it is preferable to use a surfactant in the photosensitive layer in order to promote developability and improve the coated surface state. Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and fluorosurfactants. Surfactant may be used independently and may be used in combination of 2 or more type.

(Hydrophilic polymer)
In the present invention, a hydrophilic polymer can be contained in order to improve developability and dispersion stability of microcapsules.
Examples of the hydrophilic polymer include hydroxy group, carboxyl group, carboxylate group, hydroxyethyl group, polyoxyethyl group, hydroxypropyl group, polyoxypropyl group, amino group, aminoethyl group, aminopropyl group, ammonium group, Preferred examples include those having a hydrophilic group such as an amide group, carboxymethyl group, sulfonic acid group, and phosphoric acid group.

The hydrophilic polymer preferably has a weight average molecular weight of 5000 or more, more preferably 10,000 to 300,000. The hydrophilic polymer may be any of a random polymer, a block polymer, a graft polymer, and the like.
The content of the hydrophilic polymer in the photosensitive layer is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total solid content of the photosensitive layer.

(Coloring agent)
In the present invention, a dye having a large absorption in the visible light region can be used as an image colorant. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), etc., and JP-A-62-2 And dyes described in Japanese Patent No. 293247. Also, pigments such as phthalocyanine pigments, azo pigments, carbon black, titanium oxide, etc. can be suitably used.

  These colorants are preferably added since it is easy to distinguish an image area from a non-image area after image formation. The amount added is preferably 0.01 to 10% by mass with respect to the total solid content of the image recording material.

(Bake-out agent)
In the photosensitive layer of the present invention, a compound that changes color by an acid or a radical can be added in order to form a printout image. As such a compound, various dyes such as diphenylmethane, triphenylmethane, thiazine, oxazine, xanthene, anthraquinone, iminoquinone, azo, and azomethine are effectively used.

  A suitable addition amount of the dye that changes color by acid or radical is 0.01 to 15% by mass relative to the solid content of the photosensitive layer.

(Polymerization inhibitor)
In order to prevent unnecessary thermal polymerization of the radical polymerizable compound during the production or storage of the photosensitive layer, it is preferable to add a small amount of a thermal polymerization inhibitor to the photosensitive layer of the present invention.
Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t- (Butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), N-nitroso-N-phenylhydroxylamine aluminum salt are preferred.
The addition amount of the thermal polymerization inhibitor is preferably about 0.01 to about 5% by mass with respect to the total solid content of the photosensitive layer.

(Higher fatty acid derivatives, etc.)
In order to prevent polymerization inhibition by oxygen, a higher fatty acid derivative such as behenic acid or behenamide is added to the photosensitive layer of the present invention so that it is unevenly distributed on the surface of the photosensitive layer during the drying process after coating. May be. The amount of the higher fatty acid derivative added is preferably from about 0.1 to about 10% by weight based on the total solid content of the photosensitive layer.

(Plasticizer)
The photosensitive layer of the present invention may contain a plasticizer. Examples of the plasticizer include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dioctyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, diallyl phthalate; Glycol esters such as glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, triethylene glycol dicaprylate; Phosphate esters such as tricresyl phosphate and triphenyl phosphate Diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dibutyl sebacate, dioct Ruazereto, aliphatic dibasic acid esters such as dibutyl maleate; polyglycidyl methacrylate, triethyl citrate, glycerin triacetyl ester, butyl laurate in. The plasticizer content is preferably about 30% by mass or less based on the total solid content of the photosensitive layer.

(Inorganic fine particles)
The photosensitive layer of the present invention may contain inorganic fine particles in order to improve the cured film strength of the image area. As the inorganic fine particles, for example, silica, alumina, magnesium oxide, titanium oxide, magnesium carbonate, calcium alginate or a mixture thereof can be preferably mentioned. Even if they are not photothermally convertible, they can be used for strengthening the film, enhancing interfacial adhesion by surface roughening, and the like. The inorganic fine particles preferably have an average particle size of 5 nm to 10 μm, and more preferably 0.5 to 3 μm. Within the above range, it is possible to form a non-image portion excellent in hydrophilicity that is stably dispersed in the photosensitive layer, sufficiently retains the film strength of the photosensitive layer, and does not easily cause stains during printing.
The inorganic fine particles as described above can be easily obtained as a commercial product such as a colloidal silica dispersion.
The content of the inorganic fine particles is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total solid content of the photosensitive layer.

(Low molecular hydrophilic compound)
The photosensitive layer of the present invention can contain a hydrophilic low molecular weight compound for improving developability. Examples of the hydrophilic low-molecular compound include water-soluble organic compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like, and ether or ester derivatives thereof, glycerin, Polyhydroxys such as pentaerythritol, organic amines such as triethanolamine and diethanolamine monoethanolamine and salts thereof, organic sulfonic acids such as toluenesulfonic acid and benzenesulfonic acid and salts thereof, organic phosphonic acids such as phenylphosphonic acid and the like Organic carboxylic acids such as salts, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, amino acids and their salts, and organic quaternary amines such as tetraethylamine hydrochloride Salt, and the like.

  In addition to the above, the photosensitive layer of the present invention can contain, for example, a cosensitizer.

<Formation of photosensitive layer>
The photosensitive layer of the present invention is formed by preparing or applying a coating solution by dispersing or dissolving the necessary components described above in a solvent. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyllactone, toluene, water, and the like. However, the present invention is not limited to this. These solvents are used alone or in combination. The solid content concentration of the coating solution is preferably 1 to 50% by mass.
The photosensitive layer of the present invention can be formed by preparing a plurality of coating solutions in which the same or different components are dispersed or dissolved in the same or different solvents, and repeatedly applying and drying a plurality of times.

The coating, the photosensitive layer coating amount on the support obtained after drying (solid content) may be varied according to the intended purpose, generally 0.3 to 3.0 g / m ² is preferred. Within this range, good sensitivity and good film properties of the image recording layer can be obtained.
Various methods can be used as a coating method. Examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.
<Protective layer>
The lithographic printing plate precursor according to the invention is preferably provided with a protective layer (oxygen blocking layer) on the photosensitive layer in order to block diffusion and penetration of oxygen that hinders the polymerization reaction during exposure. The protective layer used in the present invention has an oxygen permeability A of 1.0 ≦ A ≦ 20 (mL / m ² · day) at 25 ° C. and 1 atm.
) Is preferable. When the oxygen permeability A is extremely low at less than 1.0 (mL / m ² · day), unnecessary polymerization reaction occurs at the time of production and raw storage, and unnecessary fogging and image streaking occur during image exposure. The problem that fatness arises arises. Conversely, when the oxygen permeability A exceeds 20 (mL / m ² · day) and is too high, the sensitivity is lowered. The oxygen permeability A is more preferably 1.5 ≦ A ≦ 12 (mL / m ² · day), and further preferably 2.0 ≦ A ≦ 10.0 (
mL / m ² · day). In addition to the oxygen permeability described above, the properties desired for the protective layer further do not substantially inhibit the transmission of light used for exposure, have excellent adhesion to the photosensitive layer, and are easy in the development process after exposure. It is desirable that it can be removed. The device concerning such a protective layer has been conventionally made, and is described in detail in US Pat. No. 3,458,311 and JP-B-55-49729.

As a material that can be used for the protective layer, for example, a water-soluble polymer compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, vinyl alcohol / vinyl phthalate copolymer, vinyl acetate / vinyl are used. Examples include water-soluble polymers such as alcohol / vinyl phthalate copolymer, vinyl acetate / crotonic acid copolymer, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid, and polyacrylamide. Or they can be mixed. Of these, the use of polyvinyl alcohol as the main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability.
Furthermore, the protective layer in the lithographic printing plate precursor according to the invention preferably contains an inorganic stratiform compound for the purpose of improving oxygen barrier properties and photosensitive layer surface protection.
Here, the inorganic layered compound is a particle having a thin flat plate shape. For example, the following general formula A (B, C) _2-5 D ₄ O ₁₀ (OH, F, O) ₂
[However, A is any one of K, Na, and Ca, B and C are any of Fe (II), Fe (III), Mn, Al, Mg, and V, and D is Si or Al. And mica groups such as natural mica and synthetic mica, talc, teniolite, montmorillonite, saponite, hectorite, zirconium phosphate and the like represented by the formula 3MgO.4SiO.H ₂ O.

In the mica group, examples of natural mica include muscovite, soda mica, phlogopite, biotite and sericite. As the synthetic mica, fluorine phlogopite KMg ₃ (AlSi ₃ O ₁₀
) F ₂ , Potassium tetrasilicon mica KMg _2.5 Si ₄ O ₁₀ ) Non-swelling mica such as F ₂ , and Na tetrasilicic mica NaMg _2.5 (Si ₄ O ₁₀ ) F ₂ , Na or Li teniolite (N
_{a, Li) Mg 2 Li (} Si 4 O 10) F 2, montmorillonite of Na or Li hectorite _{(Na, Li) 1/8 Mg 2} /5 Li 1/8 (Si 4 O 10) F 2 , etc. Examples include swelling mica. Synthetic smectite is also useful.

  As for the particle diameter of the inorganic stratiform compound used in the present invention, the average major axis is 0.3 to 20 μm, preferably 0.5 to 10 μm, particularly preferably 1 to 5 μm. The average thickness of the particles is 0.1 μm or less, preferably 0.05 μm or less, particularly preferably 0.01 μm or less. For example, among inorganic layered compounds, the size of the swellable synthetic mica that is a representative compound is about 1 to 50 nm in thickness and about 1 to 20 μm in surface size.

  The protective layer coating solution thus prepared is applied onto the photosensitive layer provided on the support and dried to form a protective layer. The coating solvent can be appropriately selected in relation to the binder, but when a water-soluble polymer is used, it is preferable to use distilled water or purified water. The method for applying the protective layer is not particularly limited, and a known method such as the method described in US Pat. No. 3,458,311 or Japanese Patent Publication No. 55-49729 can be applied. . Specific examples of the protective layer include blade coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, and bar coating.

The coating amount of the protective layer is preferably in the range of 0.05 to 10 g / m ^{2 in} terms of the coating amount after drying. When the inorganic layered compound is contained, 0.1 to 0.5 g / The range of m ² is more preferable, and when the inorganic layered compound is not contained, the range of 0.5 to 5 g / m ² is more preferable.

<Support>
The support used in the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate-like hydrophilic support. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate) Cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), and paper or plastic films on which the above-mentioned metals are laminated or deposited. Preferable supports include a polyester film and an aluminum plate. Among these, an aluminum plate that has good dimensional stability and is relatively inexpensive is preferable.

  The thickness of the support is preferably from 0.1 to 0.6 mm, more preferably from 0.15 to 0.4 mm, and even more preferably from 0.2 to 0.3 mm.

The surface roughening treatment of the aluminum plate is performed by various methods. For example, mechanical surface roughening treatment, electrochemical surface roughening treatment (surface roughening treatment for dissolving the surface electrochemically), chemical treatment, etc. Surface roughening treatment (roughening treatment that chemically selectively dissolves the surface).
As a method for the mechanical surface roughening treatment, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used.
Examples of the electrochemical surface roughening treatment include a method in which an alternating current or a direct current is used in an electrolytic solution containing an acid such as hydrochloric acid or nitric acid. Another example is a method using a mixed acid as described in JP-A-54-63902.

  The surface-roughened aluminum plate is subjected to an alkali etching treatment using an aqueous solution of potassium hydroxide, sodium hydroxide or the like, if necessary, further neutralized, and if desired, wear resistant. In order to increase the anodic oxidation treatment.

As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, hydrochloric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.
The conditions for anodizing treatment vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, an electrolyte concentration of 1 to 80% by mass solution, a liquid temperature of 5 to 70 ° C., a current density of 5 to 60 A / d m ² , voltage 1 to 100 V, and electrolysis time 10 seconds to 5 minutes are preferable. The amount of the anodized film formed is preferably from 1.0 to 5.0 g / m ^2, and more preferably 1.5 to 4.0 g / m ^2. Within this range, good printing durability and good scratch resistance of the non-image area of the lithographic printing plate can be obtained.

  As the support used in the present invention, the substrate having the above-mentioned surface treatment and having an anodized film may be used as it is, but for further improvement in adhesion to the upper layer, hydrophilicity, resistance to contamination, heat insulation and the like. If necessary, it contains a micropore enlargement treatment, a micropore sealing treatment, and a hydrophilic compound described in Japanese Patent Application Laid-Open Nos. 2001-253181 and 2001-322365. A surface hydrophilization treatment immersed in an aqueous solution can be selected as appropriate. Of course, these enlargement processing and sealing processing are not limited to those described above, and any conventionally known method can be performed.

  The hydrophilization treatment is described in the specifications of US Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There are such alkali metal silicate methods. In this method, the support is immersed in an aqueous solution such as sodium silicate or electrolytically treated. In addition, the treatment with potassium zirconate fluoride described in JP-B 36-22063, U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689, And a method of treating with polyvinylphosphonic acid as described in the specification of No. 272.

<Undercoat layer>
In the lithographic printing plate precursor according to the invention, it is preferable to provide an undercoat layer of a compound containing a polymerizable group on a support. When an undercoat layer is used, the photosensitive layer is provided on the undercoat layer. The undercoat layer reinforces the adhesion between the support and the photosensitive layer in the exposed area, and easily peels the photosensitive layer from the support in the unexposed area, thereby improving the developability.
As the undercoat layer, specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679, JP-A-2-304441. The phosphorus compound etc. which have the ethylenic double bond reactive group of description are mentioned suitably. Particularly preferred compounds include compounds having a polymerizable group such as a methacryl group and an allyl group and a support-adsorptive group such as a sulfonic acid group, a phosphoric acid group and a phosphoric acid ester. A compound having a hydrophilicity-imparting group such as an ethylene oxide group in addition to the polymerizable group and the support-adsorbing group can also be exemplified as a suitable compound.
The coating amount (solid content) of the undercoat layer is preferably 0.1 to 100 mg / m ² ,
More preferably, it is 30 mg / m ² .

<Back coat layer>
After the surface treatment is performed on the support or after the undercoat layer is formed, a back coat can be provided on the back surface of the support, if necessary.
Examples of the back coat include hydrolysis and polycondensation of organic polymer compounds described in JP-A-5-45885, organometallic compounds or inorganic metal compounds described in JP-A-6-35174. A coating layer made of a metal oxide obtained in this manner is preferred. Among them, Si (OCH3) 4, Si (OC 2 H 5) 4, Si (OC 3 H 7) 4,
It is preferable to use a silicon alkoxy compound such as Si (OC ₄ H ₉ ) ₄ because the raw material is inexpensive and easily available.

1 is a configuration diagram of an automatic developing device according to a first embodiment of the present invention. It is a graph which shows the relationship of the fatigue degree of a developing solution with respect to a processing area, and the amount of accumulated waste liquids. It is a block diagram of the automatic developing apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram of the automatic developing apparatus which concerns on 3rd Embodiment of this invention.

Explanation of symbols

4 Photosensitive planographic printing plate (PS plate)
6 Developing Unit 10 Drying Unit 12 Side Plate 14 Insertion Port 16 Conveying Roller (Loading Roller)
DESCRIPTION OF SYMBOLS 18 Rubber blade 20 Developing tank 22 Conveyance roller 24 Brush roller 26 Squeeze roller 27 Plate detection sensor 28 Backup roller 36 Guide roller 38 Skewer roller 40 Discharge port 46 Passage 50 Control device 51 Control ROM and RAM
52 Time measuring section 55 Developer storage tank 58 Developer 60 shielding lid 62 Rubber blade 71 Developer circulation pump 73 Conductivity sensor 74 Developer supply pump 80 First circulation pipe 90 Second circulation pipe 98 Display device 99 Alarm Apparatus 100, 200, 300 Automatic developing device

Claims (4)

The photosensitive lithographic printing plate exposed imagewise is immersed in the developer contained in the developer tank for development, and the developer replenisher is replenished to the developer in the developer tank to maintain the developer activity to a certain limit. It is a photosensitive lithographic printing development processing method held within,
After filling the developing tank with a predetermined volume of the lithographic printing plate with an undeveloped developer, the photosensitive lithographic printing plate is immersed in the developing tank until the fatigue level of the developer reaches the limit. A method for developing a photosensitive lithographic printing plate, in which replenishment of a development replenisher is started after development processing and the fatigue level of the developer reaches a limit.   2. The method for developing a photosensitive lithographic printing plate according to claim 1, wherein the photosensitive layer of the photosensitive lithographic printing plate contains a polymerization initiator and a polymerizable compound.   The developing process for a photosensitive lithographic printing plate according to claim 1 or 2, wherein the developer in the developing tank has a pH of 2 to 10 and contains 5 to 30% by weight of a surfactant. Method.   The amount of water based on a preset amount of water evaporation of the developer per unit time is replenished to the developer in the developer tank to keep the developer concentration constant. The development processing method of the photosensitive lithographic printing plate of description.

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